RESEARCH ARTICLE Chloropicrin Emission Reduction by Soil Amendment with Biochar

Biochar has sorption capacity, and can be used to enhance the sequestration of volatile or-ganic contaminants such as pesticides in soil. Chloropicrin (CP) is an important soil fumi-gant for the production of many fruit and vegetable crops, but its emissions must be minimized to reduce exposure risks and air pollution. The objective of this study was to de-termine the capacity of biochar to adsorb CP and the effect of biochar amendments to soil on CP emission, concentration in the soil gas phase, degradation in soil and CP bioactivity for controlling soil borne pests. CP emission and concentration in the soil air phase were measured from packed soil columns after fumigant injection at 20-cm depth and application of selected doses of biocharto the surface 5 cm soil. Laboratory incubation and fumigation experiments were conducted to determine the capacity of biochar to adsorb CP, the effects on CP degradation and, separately, CP’s bioactivity on soil borne pests in soil amended with biochar. Biochar amendment at 2 % to 5 % (w/w) greatly reduced total CP emission losses by 85.7 %- 97.7 % compared to fumigation without biochar. CP concentrations in the soil gas-phase, especially in the top 5 cm of soil, were reduced within 48 h following applica